In this study we will investigate the role of flight tone in the mating behavior of medically important mosquitoes. Little is known this most critical aspect of mosquito life history. Specifically, we will test the hypothesis that flight tone acts as a mechanism for the assessment of potential mates. To test this hypothesis, we will focus on three aims. First, controlled ethnographic laboratory studies will determine the effect of flight tone interactions on male and female mating behaviors in free flight. Next, recordings of mosquitoes in natural mating aggregations will be collected and compared with laboratory observed results. Finally, we will develop novel molecular methods to measure reproductive success of males in field populations in order to determine if phenotypic information communicated by flight tone is utilized by females in nature. The results of these experiments will be applied to the assessment of transgenic mosquitoes to determine their ability to compete with wild-type males. The long-term goals of the project are to illuminate understudied areas of mosquito behavioral ecology and to identify novel targets for disease control. The test species, Aedes aegypti, Anopheles gambiae, and Anopheles arabiensis are three of the most important disease vectors globally. The control of these vector populations is critical to controlling the current and emerging threats of malaria and dengue fever. We propose to investigate the mating biology of two major mosquito vectors of human pathogens. The proposed research would enhance the capacity to control these species and thus the diseases which they transmit.